[Stubits]

Ok, I am thinking about doing the plumbing for an addition myself and would very much appreciate your help in laying it out. It is a small addition, just 150 sq. ft. spread out over three floors (so, approximately 50 sq. ft. per floor. In the rear of the house (where the addition will be) the basement is entirely above grade. This will be heavy in plumbing as the 2nd level of the addition will have a half bath and the 3rd level a full bath.

My plan right now is to run a 3" stack up one corner of the addition where both baths will tie into. This "stack" (not sure if this is the right term in this application) will tie into the house's main 3" cast iron stack (which currently services 1 full bath). In general, does this work? In order to get this where it needs to be it will require 3 long sweep 90's, is that overly problematic?

Can I run the 3" stack right up and out the roof and use it to vent the various fixtures? I know each fixture needs its own vent, but can I tie it all up together in the attic and have just one protrusion through the roof?

So, can I check dwv sizes?

Toilet - 3" drain, 2" vent
Lavatory - 1.5" drain, 1.5" vent
Tub/shower - 2" drain, 1.5" vent

Am I right on these?

[massplumber2008]

Hi Stubits...

3 long sweep 90s is a bit problematic, but if you install a wye/1/8th combo. fitting with a cleanout in place of one or two of the 90s you should be fine. Otherwise, you will need to install a dandy cleanout after every 3" long sweep... ok?

All DWV sizes are correct as you stated them..

Now, we need to find out if wet venting is allowed in your area (call local inspector if need be). If it is allowed there will be LESS WORK (see picture on left of big picture).

If only individual vents are allowed in your area then there will be a bit more work needed.. see picture on right below.

You will connect vents and run them up to the 3rd floor where you will probably be best to connect the vents into the VENT STACK (now) at about 48" off finish floor and then run the 3" up and out as you noted...

You can also connect the vents in the attic if that is easier...

There is a lot more rules, like pitch for drains and vents, how vents connect together, hanging pipes, drilling joists, where cleanouts belong, how tall to make the vent past the roof line, etc. We can go over that as you fine tune your plan.. OK?

Let me know if you have more questions...

MARK

[Stubits]

Mark-

Wow! This is great. Thanks!

We are governed by 2000 International Plumbing Code which I believe allows wet venting, no?

Now, for the 90's, let me try and explain their function and maybe you can help me find an alternative. The 3" stack will run vertically up the left rear corner of the addition. Starting from the roof, it will come down to the ceiling of the basement level where it needs to run horizontally (about 5') to the right rear corner of the addition. At this point it needs to 90 into the existing building where it will run approximately 15' (in a soffit) along the basement ceiling into our utility closet where it will finally 90 back to the left about 2' to tie into the main stack. Complicated, I know. Does it make sense? Effectively this needs to occur because the main stack is on the far side of our air handler, so the pipe cannot just run straight.

Any thoughts?

[massplumber2008]

Hey again...

If there is no other alternative, such as a pipe underground that you think you might be able to get to then you have no choice...

Most important on all these turns is simply going to be to install cleanouts where they can be accessed if needed. If necessary, can also install an access panel for future.

In terms of the IPC I'm pretty sure they allow wet venting, but can't be 100% sure here because even if IPC allows it, it may still not be allowed inyour town/state... need to check with local inspectional services department to be sure.

Keep us posted as you move along...

MARK

[Stubits]

Unfortunately the basement is a finished space and going through the floor would be overly disruptive, I think.

So, a "dandy cleanout" is required by code at each 90, right? Before or after? Obviously if it is behind drywall, then I'll need an access panel. The cleanout cannot be drywalled over, I assume.

How would I use the wye/1/8th combo. Fitting you mentioned earlier instead?

Thanks!

[massplumber2008]

Actually, the wye 1/8th combination fitting can almost be used interchangeably with the long sweep 90... as long as you install accessible cleanouts in line.

In fact, the long sweep 90 and the dandy cleanout is probably best in this case as it allows you to snake the drain in both directions of the drain... ;) The end clean out only allows for cleaning in one direction.

See pictures.

MARK

[Stubits]

Great.

I could be way off on this, but I seem to remember from another post that wyes are used for horizontal connections and sanitary tees for vertical?

[massplumber2008]

Correct!

Sanitary tees can also be used on the horizontal to pick up vents as long as they are rolled above the center of the drain line... ;)

[Stubits]

Ok, great. That's what I thought. I am starting to work this out in my mind and will try and get something down on paper shortly. Will run it by you then. Thanks!


Mark-

Would it be too much to add a washer into this?


Also, here is a very rough layout of the bath room as we'd like it.

Just a couple of things to point out.

1) The black dot in the upper right hand corner is the 3" stack.

2) On both floors, the wall on the right and the wall on the bottom are original 8" thick solid brick walls. On the main level, we will be framing the wall out with 2x4 and covering in drywall. On the 2nd level, we will be leaving the brick exposed.

3) The floor joists will be 2x12 and will run from left to right (the long way). The floor for the 2nd level will actually be sistered 2x12 because we will be installing an antique clawfoot tub.

4) The left wall and the upper wall are both exterior walls. I haven't decided if I will frame them using 2x4 or 2x6.

So, that said, what do you think? Is this a reasonable layout? It seems intuitive to me. How about from a plumbing perspective?

With the joists running from left to right, I think the only drain that will need to run through a joist is the 2" tub drain, right?

What are the rules for notching or boring studs in a load bearing wall? Is it no more than 40%?

I've spoken with a local plumber who confirmed that wet venting is allowed, but I have a call into the inspector's office.

Thanks!

[massplumber2008]

Hi..

If you want to add a washing machine is there any chance you can connect the 3" from the new bathrooms into a 4" pipe instead of the 3" from the existing bathroom? Let me know.

DO not NOTCH studs...drill them. The 1/3 rule applies to joists not studs. With studs you want to keep the hole as small as possible is all you can do.

The layout seems fine... pretty much lays out as I posted at the first picture with WET VENTING... just slightly different.

I'll try to draw up a plan for you in the next day or so... won't take too long.

Answer my question.

Chat soon.

MARK

[Stubits]

I do not believe I have a 4" pipe anywhere, at least not above ground, unless I am misreading things. I will post a photo tonight, in case you can see something I am missing. Basically, there is a 3" cast iron that comes up out of the concrete slab and goes straight up to the bathroom. I believe it is 3" top to bottom, but could be wrong.

On the studs, I'll be sure to drill, not notch. My concern is the 2nd floor lav where the 1.5" drain line will have to run through a couple of exterior, load bearing studs. Due to space issues I am thinking of framing out in 2x4, but can I drill a hole for a 1.5" pipe through a 2x4? Also, I will need to drill through the top and bottoms of the studs to bring up the various vents. (I will run the 3" stack in a chase on the corner so I won't have to run it in the wall.

[massplumber2008]

You can drill a 2.25" hole for 1.5" PVC pipe...works fine in a 2"x4" stud (i.e., 1.75" x 3.75").

As you noted, you can bring the stack up in the corner or you could build the wall using 2" x 6" studs....you decide.

I'll wait for the picture...There has to be someplace where there is 4" in the house? Where is the main cleanout? Let me know.

[Stubits]

Hmm. Now you have me thinking a bit more about the current setup.

There's actually only 1 cleanout in the whole house that I am aware of. The 3" stack that services the upstairs bathroom passes through a large cleanout about 3' or so before it enters the concrete slab. Perhaps the pipe after the cleanout is 4"?

[massplumber2008]

See if you can post a picture... see what we think here. I have almost never seen a home with only 3"... hmmm?

Let me know.

[Stubits]

I will try and get a picture tonight.

For what it's worth, it's an older home, circa 1930 (but you're up in Boston where homes are even older). I know there's only 2 stacks, a 2" and what looks to be a 3", but I could be wrong.

Can I measure it? If so, how?

[massplumber2008]

Yeah... I've been all over new england states and have only seen 3" in a few cottages...so interesting if you only have 3".

Most hubs of cast iron pipe/fittings have a number and an SV (service weight) or an XH (extra heavy) cast into them (raised above surface)... see if you can find the number and which letters are present.

[Stubits]

This would be on the hub (the cleanout?) itself? In indeed this is a 3" pipe into a 4" pipe, there should be two numbers on the hub?

I will check on that tonight, for sure.

Also, what do SV and XH stand for?

[massplumber2008]

Reread my last post regarding SV and XH... ok?

The hub is the enlarged bulbous end on a pipe or on a fitting... see picture.

[Stubits]

Great, will do!

[massplumber2008]

Sorry... I posted an updated picture while you were writing.